How to close a thread when using autoreload

[Yarkee]

The code frame is as follow:

threading.Thread(target=my_thread_func).start()
http_server = tornado.httpserver.HTTPServer(Application(),
xheaders=True)
http_server.listen(8080)
io_loop=tornado.ioloop.IOLoop.instance()
tornado.autoreload.start(io_loop)
io_loop.start()

As we know, if we use tornado.autoreload.start(), tornado will reload
the code when we modify some code and save it.
Everytime tornado reload, “threading.Thread(target-
my_thread_func).start() ” will be called and it will exists more and
more threads.
How to close the thread when tornado reload in case of more and more
threads?

[Ben Darnell]

Autoreload uses the exec() system call, which as a side effect will
automatically destroy all threads in the current process.

-Ben

[Yarkee]

exec() will copy all process context to a new process, which contains
all the fd.
The thread "my_thread_func" as I mentioned above, will creat some
socket fd.
the result of Autoreload is that: thread is closed, but socket fd not.
More and more fd will be reversed but not be closed, and the rev_bufs
of those socket fds are still receiving tcp segment.
It is awful.

[Ben Darnell]

Yes, this is why in general it's a good idea to use the FD_CLOEXEC
flag. Tornado does this for all socket fds it opens. If you cannot
easily set FD_CLOEXEC on all fds your application uses, you can use
tornado.autoreload.add_reload_hook to close any remaining files
(perhaps using os.closerange(3, MAX_FD). 3 is the first regular file
descriptor; 0, 1, and 2 are stdin, stdout, and stderr)

http://www.tornadoweb.org/documentation/autoreload.html#tornado.autoreload.add_reload_hook

-Ben

[Yarkee]

Excellent solution. Thks!

On 9月29日, 上午10时27分, Ben Darnell <b...@bendarnell.com> wrote:
> Yes, this is why in general it's a good idea to use the FD_CLOEXEC
> flag.  Tornado does this for all socket fds it opens.  If you cannot
> easily set FD_CLOEXEC on all fds your application uses, you can use
> tornado.autoreload.add_reload_hook to close any remaining files
> (perhaps using os.closerange(3, MAX_FD).  3 is the first regular file
> descriptor; 0, 1, and 2 are stdin, stdout, and stderr)
>

> http://www.tornadoweb.org/documentation/autoreload.html#tornado.autor...